package edu.gdkm.demo;

public class Demo2 {
    public static void main(String[] args) {
        int i=1;
        System.out.println(i);
        double a = 5.99e5;
        System.out.println(a);
        //字符
        char ch1 = 'a' ;
        System.out.println(ch1);
        char ch2 = '\n' ;
        System.out.println(ch2);
        char ch3 = '中' ;
        System.out.println(ch3);
        //字符串，由字符的数组构成，一般会将它当成一种常量来使用
        System.out.println("a2\t中国 梦");
        String s = "哈哈哈";
        System.out.println(s);
        boolean b1 = true;     //  3 > 5 ==> false    3 < 5 ==>true
        boolean b2 = false;
        System.out.println(3>5);  //  >  <  >=  <=  != ==
        //null 对象为空
        String s2 =null;
        System.out.println();
    }
}
